I stayed at an Amanresorts for the first time around 12 years ago. By then, we were just about able to afford the accommodation and did not have any amount of money left to eat/drink/go on activities there. During a holiday, we would go to simple hotels for most days, and then splurge in an Aman at the end. We would maybe stay 2 or 3 nights, but only have one meal there and do one activity and for the rest we would go out for food or by snacks and eat in our room. Still we loved every minute of it. It is nicer to go now when we can afford taking full advantage of everything offered in the resort, but I never regret that we went before. I do not know if you would feel the same way. If you would stay there and think about the high cost compared to alternatives all the time, I do think you should do it. The only way to find out, is to stay. Maybe just one night, arriving early one day and leave late the next day to fully enjoy? Amans are normally very flexible in terms of check in and check out times as long as they are not fully booked.

As mentioned in another thread, meal prices at Amans are same as in expensive restaurants in Europe or the US. Special meals (like private BBQ on the beach or similar) even more expensive, but very special. Not possible to give you costs of activities in general, but you can always write to the different resorts directly to get their activities lists with costs. Or if you ask for one specific activity, I can try to find it for you if I have the information.